/Engine/Source/Developer/TreeMap/Public/STreeMap.h
MOUSE INPUT The system calls this method to notify the widget that a mouse button was pressed within it. This event is bubbled.
Whether the event was handled along with possible requests for the system to take action.
virtual [FReply](API\Runtime\SlateCore\Input\FReply) OnMouseButtonDown ( const [FGeometry](API\Runtime\SlateCore\Layout\FGeometry) & MyGeometry, const [FPointerEvent](API\Runtime\SlateCore\Input\FPointerEvent) & MouseEvent )